Weather between Peoria, ILL and Yellowstone

Your big worry should be I-74 going west out of Peoria. I just traveled it from Davenport, Iowa over to Champaign. Hands down the worst stretch of cement I have been on this year. I slowed way down to avoid shaking my rig to pieces.

I-74 is the only Interstate highway I have ever seen where the DOT posts signs stating 'Rough Road Next 10 Miles'. etc. This was in several places.

We traveled to and from Ind. to S.D. from '78-'87 while living in S.D. and never had a issue in that time frame. Have done it many many times since and never had problems with weather. We were in Yellowstone in '82 in late June and no snow except going from Red Lodge,Mt. to the north east gate.

We had snow in West Yellowstone 5/25/2010 and at Mt Rushmore 5/13/2010 and had to sit in Wall SD and wait until Rafter J got plowed out

West Yellowstone is 6700 ft. elevation and Fishing Bridge in the park is 7700 so snow is likely

As it looks now in Wyoming don't think we're going to get any record snow falls this winter. We're in the third week of October and haven't had a frost yet. Days are in the 70s. (5,000 ft) Nights are in the mid 40s. Strange weather for sure. The el nino in the pacific has really brought warm weather to Wyoming.

Atlee wrote:
How likely is it to run into snow and/or freezing rain on a route between Peoria, IL and Yellowstone NP, with a stop over in the Black Hills area of SD, and Little Big Horn Battlefield Monument in Montana from the middle of May through the middle of June?

IMHO very unlikely.

Should be fine the weather will not become an issue until you approach altitude, then still very unlikely, High mountain passes may still have some snow if it was an extreme winter with record snow falls.

We generally try to travel in the spring and fall and with the exceptions stated have rarely had an issue - but being in the Motor Home we just hang around a few hours till any issue passes, but again this is an extremely rare event.

Go for it!